Wedge-Driven Hole Positioning Fingers for Small-Diameter Alignment
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Solution Overview
Problem
Existing hole positioning devices, such as air chucks, face issues with finger deformation or breakage due to rigidity limitations, especially when aligning small or requiring high opening forces, leading to low durability.
Innovation Solution
A positioning device with movable fingers and a wedge-shaped pressing member that moves in the axial direction, allowing the fingers to expand radially to align holes, supported by a movement device and biasing mechanism to prevent finger deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rigidity of the finger is increased to prevent deformation, then the finger can withstand higher opening forces, but the finger cannot be inserted into small diameter holes
Solution Approach 1:
The finger is divided into two functional parts: a thin inserted portion that fits into the hole and a thick base portion that receives the pressing force. This segmentation allows the finger to be inserted into small holes while maintaining the structural integrity needed to withstand opening forces.
Solution Approach 2:
Different parts of the finger have different cross-sectional areas optimized for their specific functions. The inserted portion has a small cross-section for fitting into holes, while the base portion has a large cross-section for receiving pressing forces without deformation.
2Manufacturing precision
If a large opening force is applied to align the holes, then the positioning accuracy is improved, but the finger may be deformed or broken due to insufficient rigidity
Solution Approach 1:
The finger structure is designed with a thick base portion that has high rigidity to withstand large opening forces, while the inserted portion remains thin for proper hole engagement. This local quality differentiation allows high positioning accuracy without finger deformation.
Solution Approach 2:
The fingers are preliminarily positioned to engage with the holes before the pressing member applies the opening force. This preliminary positioning ensures that the force is applied along the correct axis, preventing lateral deformation and improving both alignment accuracy and finger durability.
3Force
If the hole clamp is made large to provide sufficient clamping force, then the positioning capability is improved, but the clamp cannot be inserted into the holes
Solution Approach 1:
The clamping mechanism is segmented into a thin inserted portion for hole engagement and a thick base portion for force application. This allows the clamp to be inserted into holes while maintaining sufficient clamping force capability.
Solution Approach 2:
The clamp transitions from a two-dimensional planar structure to a three-dimensional structure with varying cross-sections along its length. This dimensional change allows the clamp to fit into holes while providing sufficient clamping force through its expanded base portion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances durability by preventing finger bending and improving alignment accuracy, enabling reliable insertion of members into aligned holes without frequent replacements.
Implementation Method 1
a pressing member (68) having a wedge shape and disposed so as to be in contact with the plurality of fingers (74)
Data Source
AI summary
A positioning device including a plurality of finger portions formed so as to be movable in a radial direction perpendicular to the axial direction and a wedge-shaped pressing member disposed so as to contact the plurality of finger portions. The positioning device further includes a moving device that moves the pressing member in the axial direction. By the moving device moving the pressing member in a state in which the finger portions are inserted into a plurality of hole portions of a workpiece, the finger portions are moved outward in the radial direction, thereby positioning the plurality of hole portions of the workpiece.